Achieving Color Matching Magic

For the majority of print service providers (PSPs) the road to color matching across different platforms and output devices is neither smooth nor straight.

Part of the problem is the nature of the beast. No matter how much energy, effort, and time, images printed on a gravure press are not going to exactly match images output on a digital press. “Different print technologies have their own biases and challenges,” said Dan Reid, President of RPImaging, Inc., a color management consultantcy.

There is also the consumables issue. Substrates, ink, toner, etc., all have a major influence on the end result, particularly the color.

And then, of course, there is what the PSP is, or rather, is not, doing.

Making “color matching magic” is the result of several factors, including practices implemented by the PSP.

David Hunter, one of five G7 Expert Trainers in the world and founder of Pilot Marketing Group, argues a good place to start is with the output device itself.

When purchasing a color output device, whether that device is a sheetfed press, wide-format inkjet, or digital press, print shop owners and executives need to ask vendors two questions: (1) “How repeatable and consistent is the device, day to day, job to job?” (2) “How accurately will it be able to hit a GRACoL target?”

“Every output device, whether it is from Xerox, KBA, HP, or Konica, has a definite level of precision or consistency that it is able to perform to, depending on consumables,” noted Hunter.

“If I were an owner of a print shop. I would not think about laying out money unless I knew what these two attributes – repeatability and accuracy – were for the device,” he added.

To that end, Hunter has created E-Factor, a single number that defines the quality of the color match, and is designed to close the loop between customer expectations—which he calls the Expectation Factor—and an output device’s ability to match those expectations. E-Factor may be applied to a brand, a manufacturing shop, and all the workflow components (output device, substrate variation, instrument variation, lighting variation) necessary for the successful color reproduction.

To determine their E-Factor, PSPs can upload their files to Chromachecker.com for free. “PSPs can output targets, measure them in, upload to our site, and calculate what each devices E-Factor is in order to determine if it can meet the customers expectations,” said Hunter.

A smaller E-Factor reflects a closer color match. In the real world of printing, there is no expectation of a value of zero, which would mean an exact match.

To control color across the printing production universe, the best place to start is to implement Gray Component Replacement (GCR). GCR reduces wiggle room, said Marc Welch, GMG Director of Strategic Accounts, in both offset and non-UV digital presses.

This is because a GCR separation uses black throughout the tonal range and with the proportions of C, M, and Y in the mid- and quarter-tones reduced, the color in GCR separated images is more stable. Solid C, M, and Y ink densities naturally vary through a press run.

“You have to figure how that press wants to behave,” said Welch. “You have to figure out how you can make it run in an optimum way to get the most color and most repeatability and feed it separations that land that device.”

You can classify digital presses broadly in two groups, explained Welch. The first group is UV curable inkjet printers, such as those used in wide-format printing and digital label printing. Because they are UV curable, they are super stable, they don’t ‘wiggle’ and are linear across different substrates; once calibrated, it behaves the way you want it to.

The second group of output devices –toner and aqueous-based digital printers –behave more like offset presses. They ‘wiggle’ similarly to an offset press, so instead of calibrating, you have to employ guard rails to contain the movement. “There’s no point in calibrating an offset or aqueous-based printer; over the course of the day, the delta e could change five times a day,” said Welch.

Employing GCR helps contain the variability, keeping color consistent through the run.

Running a press with poor color management is chasing color and throwing away valuable profits, noted Shoshana Burgett, Director of Corporate Strategy and Customer Insights, X-Rite Pantone.

It means there will be a lot of waste—which no PSP can afford in this current environment –and rework, the result of inaccurate color. Much of this waste can be captured by starting the color management process well before a job reaches the press, Burgett said. This includes evaluation of incoming materials, especially substrates and inks; proper calibration of proofing devices and monitors that will be used in the prepress process; specifications to meet; evaluation of color in a controlled lighting situation, and having clients signing off under the right lighting conditions; and education of customers about how color should be specified, viewed, and approved.

“Commercial and package printers who have implemented color management best practices find that they have more credibility with their customers, even to the extent of being able to minimize or eliminate expensive press checks, and their own operations run more smoothly and profitably,” Burgett said.

Closed-loop color control also requires a means to capture color data; a way to characterize that device; a means of color conversion; a reference condition such as to GRACoL set to your specific output device; and a way to report on those specifications.

To achieve color control, you have to absolutely 100% have a measurement device, says Reid. “If you wan to control or match color, you have to be able to measure color. You can’t do this by your eyeballs; you can’t assume the color is right.”

You also have to make sure the measurement device is useful for the printing device and media that are being used. New spectrophotometers are now available that allow you to measure the optical brightness in the paper, for more realistic measurement.

One such example is X-Rite eXact spectrophotometer with Scan Option. which takes into consideration optical brighteners in both substrates and inks. It allows printers to validate that presses are hitting the G7 condition without the need for a separate press run. X-Rite eXact quickly—in less than one second—measures True M1 and M0, M2 and M3 simultaneously for both spot and scan readings.

Along with a spectrophotometer – and a light booth – shops should invest in software solutions that enable them to align color measurement instruments with each other and keep them operating within specifications. This allows shops with multiple presses or production sites to all be aligned to the same specification. “You can’t get to the right color if one device is speaking a different language than the next,” said Burgett.

G7, Idealliance’s set of specifications for achieving gray balance, is a well-known method to achieve visual similarity across all print processes. It provides consistent neutrality relative to the substrate, balancing out any bias before you apply color management, explained Reid, an early adopter of G7 and a G7 Certified Master Printer.

While its roots are in offset, G7 is device independent, and is designed to deliver a consistent appearance across any print platform.

Hunter touts an approach to color control and matching that aims for a common reference point. “Instead of matching device A to device B, we aim for a stake in the ground, using an industry reference such as GRACoL,” said Hunter. “There are multiple reference conditions to represent a process an agnostic aim point. “

Thinking of each device as a ‘ring’ around the stake, it doesn’t matter whether you are running inkjet, conventional or wide format, each ring has to hit the same GRACoL reference point. If they do this, they will naturally match each other.

By adhering to an industry reference point that is traceable and able to represent the Adobe Creative Suite, the default application most used for color settings, the reference print conditions all line up. There is a uniform appearance on what the customer is seeing, whether it’s on a LCD screen or in print.

A critical tool for accurate color matching are device link profiles and ink optimization workflows, including those from Alwan CMYK Optimizer, GMG ColorServer, RAMpage INKdrop, and Screen Trueflow. These applications process fully automatic conversions from one color standard to another.

ColorServer automatically and consistently converts incoming data to the required target color space – whether it is from CMYK, RGB, spot color or any other color, to, a single color standard by means of separation, re-separation, or color conversion.

The DeviceLink approach devised by GMG avoids drawbacks of ICC technology, such as re-separation of the black channel. GMG ColorServer also ensures consistent colors when converting to RGB. As a result, mobile publications or websites can be reliably produced on the basis of defined color values.

The visual color impression is preserved, even after color transformation, and regardless of the printing process, press, and substrate.

This re-separation of data, often called normalization, takes data from input space and customizes the structure of the separation to get the best result based on how the output device actually behaves, said Marc Welch, GMG’s Director of Strategic Accounts. Because data is optimally generated for different production environments, uniform print results are achieved. Data from different sources behave identically on the press.

GMG InkOptimizer, based on the GMG ColorServer, also uses GMG device link technology, along with GMG’s custom algorithms to implement the ink savings and GCR. While reduced ink usage is the most obvious benefit of running ink optimization software, the added benefit of applying GCR is stability across the print run.

Applying DeviceLink profiles, along with GCR, moves the ball down the field in terms of creating uniform appearance across a brand’s materials, said Welch.

Taking the concept of device links several steps further, at least across the packaging supply chain, is GMG’s OpenColor software, a multi-channel device link platform that is not limited to CMYK. OpenColor allows color-accurate reproductions of print processes that use spot colors and multicolor separations with more than the traditional four process colors (CMYK).

“Until OpenColor, there was no true multi-channel device link architecture,” Welch said, noting the technology, which was launched at drupe 2012, received the PIA InterTech Technology Award and FTA Technical Innovation Award in 2013. “It can map anything to anything, from 2 to 15 colors.”

It can go from four colors to seven colors, or seven colors to four.

“It’s so transformational we won’t understand what people will be able to do in three to five years,” said Welch.

Statistical process control solutions such X-Rite’s latest version of ColorCert: X-Rite Edition provides operators, management, and customers with a real-time view of color quality during production, across operators, presses, shifts, and plants. Similar to a job ticket, an operations manager or owner can easily see how each shift or site is running and can use the tools to identify areas of improvement.

“Larger shops may wish to take advantage of cloud-based solutions such as PantoneLIVE to securely store spectral values for customer or shop colors, making them available to approved stakeholders,” said Burgett. “These color values exist in two forms: Master Standards, the DNA of the color; and Dependent Standards, the values required to achieve color on a specific substrate with a specific printing technology and ink system. Achieving a PMS 032 on kraftboard can be time consuming and dependent standards provide the optimal metrics for that color on that material.”